1. Field of the Invention
This invention relates generally to the field of electrical component integration and more particularly to systems for, and methods of, arranging and connecting electrical components to be used in electrical systems such as surge protective devices (SPDs).
2. Description of Related Art
Discrete electrical components are typically integrated into an electrical system by means of a printed wiring board (PCB). Components are mounted to a PCB using well known methods such as surface mounted technology and general feedthrough technology.
Some electrical systems, such as surge protective devices (SPDs) for use in power and signaling systems, require a large number of electrical components, particularly diodes, in order to provide the voltage, clamp range and energy suppression typically required by such systems. The large number of diodes renders PCB layout design difficult for several reasons. First, the large number of discrete components laid out on the PCB produces a cumulatively large lead length within the circuit formed by the interconnection of the discrete components. A large lead length may have a detrimental effect on the operational characteristics of the circuit.
Second, a PCB having a large number of individually mounted discrete components is typically structurally unstable in that the individually mounted components may become disconnected from the PCB. This is especially true for a PCB which is part of a module card that is often removed from and reinstalled into an electrical system.
Third, depending on the physical constraints of the electrical system being designed, limitations may be placed on the size of a PCB. A size limitation on the PCB, in turn limits the number of discrete components that may be mounted on the PCB and thereby limits the functional capabilities of the circuitry on the PCB.
Hence, those concerned with the development and use of electrical component assemblies have long recognized the need for component assemblies which are relatively compact, structurally sturdy, have minimum lead length between components and are configured to provide multiple paths, thus allowing for a multitude of electronic operating characteristics and functions. The present invention fulfills these needs and others.
Briefly, and in general terms, the present invention provides a system for arranging and connecting components used in surge protective devices (SPDs) and the like. The system provides a sturdy matrix array of electrical components having minimal lead lengths and the ability to provide multiple conductive paths, thus allowing for custom circuit design based on desired electronic operating characteristics and functions.
By way of example, and not necessarily by way of limitation, the present invention in one aspect provides an electrical component assembly having a first printed circuit board PCB) having a plurality of first-PCB conductive paths communicating with at least one surface of the first PCB. The assembly also has at least one additional PCB having a plurality of additional-PCB conductive paths communicating with at least one surface of the additional PCB. The first-PCB conductive paths and additional-PCB conductive paths are located such that when the additional PCB and the first PCB are positioned so that one PCB overlies the other, the first-PCB conductive paths and the additional-PCB conductive paths are substantially aligned. The assembly also includes a plurality of electrical circuit components, each electrically connected to one of either of the first-PCB conductive paths and the additional-PCB conductive paths at one end and to another of either of the first-PCB conductive paths and the additional-PCB conductive paths at the other end. The assembly further includes at least one trace conductive path connecting at least two of either of the first-PCB conductive paths and the additional-PCB conductive paths
Thus the present invention substantially reduces the amount of wire leads within a circuit assembly by creating a unique arrangement of conductive paths, carried by the PCB, that functions as electrical junctions between components. The conductive paths also provide a bonding surface which enhances functional rigidity and electrical performance. The invention also creates a unique circuit configuration in utilizing PCB designs to create a matrix array. The invention creates an electrical junction between discrete components by bonding the components, surface to surface, using solder bonds and the PCB, itself, as a junction carrier. These conductive paths allow for parallel or series configurations in design.
In a more detailed facet, the first-PCB conductive paths and the additional-PCB conductive paths include at least one solder-filled via passing through the PCB. In another facet, the first-PCB conductive paths and the additional-PCB conductive paths further include at least one electrically-conductive junction pad communicating with the solder-filled via. The junction pad is positioned at the surface of the PCB. In still another aspect, the junction pad is substantially flush with the PCB. In yet another facet, the trace conductive path is carried on the surface of the PCB.
In a second aspect, the invention provides a SPD for electrical circuitry. The device includes first and second terminals for connection to the power and/or signal terminals of a circuit being protected. The device also includes a first printed circuit board (PCB) having a plurality of first-PCB conductive paths communicating with the surface of the first PCB and at least one additional PCB having a plurality of additional-PCB conductive paths communicating with the surface of the additional PCB. The first-PCB conductive paths and the additional-PCB conductive paths are located such that when the additional PCB and the first PCB are positioned so that one PCB overlies the other, the first-PCB conductive paths and the additional-PCB conductive paths are substantially aligned. The device also includes a plurality of electrical circuit components, each electrically connected to one of either of the first PCB conductive paths and the additional-PCB conductive paths at one end and to another of the first-PCB conductive paths and the additional-PCB conductive paths at the other end. The device further includes a plurality of trace conductive paths connecting selected first-PCB conductive paths and additional-PCB conductive paths, the first-PCB conductive paths, additional-PCB conductive paths and trace conductive paths connect the electrical circuit components to provide a means for clamping the voltage across the first and second terminals to a characteristic voltage when energized. The electrical components also provide an energizing circuit having a predetermined voltage threshold of conduction.
In a third aspect, the invention provides a SPD coupled between power lines and/or signal circuits. The device includes a first printed circuit board (PCB) having a plurality of first-PCB conductive paths communicating with the surface of the first PCB. Also included is at least one additional PCB having a plurality of additional-PCB conductive paths flush with the surface of the additional PCB. The first-PCB conductive paths and the additional-PCB conductive paths are located such that when the additional PCBs and the first PCB are positioned so that one PCB overlies the other, the first-PCB conductive paths and the additional-PCB conductive paths are substantially aligned. The device also includes a plurality of electrical circuit components, each electrically connected to one of either of the first-PCB conductive paths and the additional-PCB conductive paths at one end and to another of either of the first-PCB conductive paths and the additional-PCB conductive paths at the other end. Also included is a plurality of trace conductive paths connecting select first-PCB conductive paths and additional-PCB conductive paths. The first-PCB conductive paths, additional-PCB conductive paths and trace conductive paths connect the electrical circuit components to provide a means for clamping the voltage across said power line and neutral line to a predetermined voltage.
These and other features and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawing, which illustrate by way of example the features of the invention.